HYOLITH GUTS IN THE CAMBRIAN OF NORTHERN AUSTRALIA - TURNING HYOLITHOMORPHS UPSIDE-DOWN

A single specimen of the early Middle Cambrian (Ordian) orthothecimorp h hyolith Guduguwan hardmani with preserved gut filling has been disco vered in the Montejinni Limestone, Wise Basin, northern Australia. Thi s represents only the eighth such occurrence worldwide. The specimen i s unique among orthothecimorphs in retaining the gut filling in combin ation with the external mould of the operculum and invites revision of the accepted soft-part reconstruction in this group, whereby the oper cular lateral processes are now recognized to be ventral. Thus orthoth ecimorph conchs, if horizontal in life, would have been oriented ventr al side down, while hyolithomorphs adopted the reverse orientation: ho rizontal, ventral side up.